When MRI and CT scans harm more than help

Back strained? Getting an immediate MRI or CT scan is likely to be a waste of money and it may even be harmful, say doctors who analyzed six clinical trials of diagnostic imaging for low back pain.

Researchers at Oregon Health & Science University's evidence-based practice center compared patients who received an immediate X-ray, CT or MRI scan with patients whose doctors relied on a physical exam and history. The imaging patients fared no better in terms of relief from pain and anxiety or recovery of function for up to a year after seeking care.

Previous studies have shown that imaging may lead to harm because it can prompt doctors to perform unnecessary surgeries on spine abnormalities that turn out not to have been the cause of pain. Lead author Dr. Roger Chou said the misleading findings may cause patients to stop being active, and thus undermine recovery.

Bottom line: It's better to skip the expensive scans unless your doctor has good reason to suspect a spinal disorder that warrants surgery or an underlying condition, such as cancer or infection. The study appears in the Feb. 7 edition of The Lancet.